Allan4

Hey Mike, why don't we just get it over with and swap motors, I know you would rather have mine.......HAHAHAHA!!!!! (I'll even deliver.....

Pure Energy

Wally,

Motors are 502, 435 hp GM marine crate engines with prochargers @ 6.5 lbs. of boost @ 5300 rpm. Motors have been balanced and blueprinted, heads ported & polished, comp. valve job, Imco exhaust. Everything else is stock, forged crank and pistons. I believe compression is 8:1.

Both motors were just rebuilt because the marina damaged both engines during a sea trial and agreed to balance and blueprint during rebuild. I paid extra for the head work, and valve job.

Motors dynoed @ 640 hp @ 5700 rpm with 5.5 lbs of boost and 650 lbs torque @ 4400 rpm. But the dyno and on the water are 2 different things. Loads are not the same. Obviously with my 5300rpm and 6.5 lbs of boost.

KAAMA

Ken,

Which do you think loads the engine more....the dyno or engine/boat in water? I'm guessing the props and weight of the boat probably has something to do with it---too many inconsistant variables---right?

Walley, "DanB" made 563hp at about 5500rpm with an air-gap intake, Crane 139741 hdy roller cam on 112*lobes, World Products cast iron 308cc heads(NON PORTED), 950cfm Holley, and about 9-9.5 comp ratio. It made 620 foot pounds of torque at about 3500rpm. He dyno'd it at Tyler Crocket's shop. BTW, it was a 502. He runs his boat with Lightning headers. Thing runs real sweet.

Cattitude

Not trying to be OT- but....
Merc 454 MAGEFI + 7 lbs of Whipple = 650 hp and 740 tq that I change oil on, occasionally adjust idle speed (once in 87 hrs) and watch gages.

A pretty reasonable priced combo with EFI!

Now- when the time comes for freshening- what do I do to this combo to make it better? So far I plan on Inconel ex valves, the right felpro o-ring head gaskets and some ARP head bolts. If I'm feeling spendy I might go for some roller rockers.

I suspect there will be a market for a better cam or bigger inch shortblock for these combo's- I guess the computer would need programming and maybe some larger injectors?

Pure Energy

Kaama,

I think it may depend on the dyno. I had one guy do work for me and he said he could program the dyno to simulate launching and re-entry. Might be able to somehow program boat weight etc. to get more acurate #s. Then again he could have been full of ****. Everything else he told me was.

MIKEHTMSR24

Do what

Stock 454/385 @ the prop and probably 425 hp @ the crank at most. 425 - 650 = 225 hp increase. Is that possible
740 lbs. of tq.

My 540 with full port and polished heads with 610/625 lift maxed @ 676 lbs. of tq @ 4700.

Not saying it ain't so just askin

Cattitude

HTM- these numbers are according to Dustin, at the crank, not prop. These are stock numbers for the Whippled 502, my 454 with a little extra boost comes out similar.

So personally, I trust Dustin and the boat performance seems on par.

I do have appreciation for a good custom motor that pulls hard to 6k though- seems like they can be set up to go faster per given HP- at least per my armchair test and oso reading etc etc.

At any rate- I'm a happy customer.

Allan4

KAAMA, did DanB try any other cams????

Curious, because it sounds like we have comparable motors, but I am one size down on the Crane cam and he is making alot more power than I. Just wondering if my heads are that bad????? Thanks

KAAMA

Allan4, DanB is running a 950cfm carb compared to your 850. I really can't see why that would make a difference but maybe it does. With an 950cfm carb on the dyno, my 540's made about 16 more horsepower over the 830cfm carb, but didn't really see the increase until ABOVE 5400rpm and at some lower rpm levels the 830 carb out performed the 950. Perhaps too many variables, but at least there's one thing to think about. Also, he used some cast iron World Products 308cc heads with a .225" intake valve and 1.88" exhausts, 3-angle valve job and as I said before NO PORT WORK! He's also using a MSD ignition box. Crocket I think used some other headers on the dyno. DanB is using the Lightning's in his boat so they will be close. He only used the 139741 cam in his engine for dyno testing and his boat as they are very expensive. That's about all I can tell you bud!

Ken, sorry to hear about your bad expereinces with your engine builder as I have just parted ways with the engine builder I was using too.

DanB

Allan
Kaama pretty much sumed it up
622 lbs tq@3400, 529lbs @ 5600
563 hp @ 5600
The only thing different in my combo is the Crane 741 cam, (straight up) merlin 310 VR heads that Valako cleaned up (cc chambers, 3 angle valve job) Crane rockers, 950cfm Holley HP4150 w/82 jets front and rear, 1" carb spacer, K&N 7" tall filter
One other thing was I had the block squared and decked about 10thou (I think) to increase quench. Run a .038 head gasket.
JE 9.8-1 Pistons W/C&A rings. 34* timing all in @3400rpm
Our #'s are pretty close, so I dont think your far off, might just be the cam?
Dan